Tool kit for installation of a strike plate for a latch bolt of a door



Dec. 10, 1963 c. c. HILLGREN TOOL KIT FOR INSTALLATION OF A STRIKE PLATE FOR A LATCH BOLT OF A DOOR 2 Sheets-Sheet 1 Filed Aug. 18, 1959 IN V EN TOR. CmeL 6. 117/1, 1. GEE/V flrraeA/Exs'.

Dec. 10, 1963 c. c. HILLGREN 3,113,600

TOOL KIT FOR INSTALLATION OF A STRIKE PLATE FOR A LATCH BOLT OF A DOOR Filed Aug. 18, 1959 2 Sheets-Sheet 2 IN V EN TOR. 6:442; 61 E; L @eE/v flrraewsys.

United States Patent This invention relates to a tool kit for use in installing a strike plate in a door frame in proper alignment with a latch bolt of a door.

In the installation of a door an especially vexatious and time consuming operation is the positioning of the strike plate in a door frame for receiving a latch bolt of the door latch. It is important that the strike plate opening be accurately aligned with the latch bolt when the door is in closed position whereby the latch bolt will hold the door abu-tted flush against the stop in the door frame to prevent rattling of the door.

For conventional door latches the strike plate is relatively small in area and it is important that the bolt receiving opening in the door frame be made to a limited size so that there will be suflicient space around the bolt receiving opening for securing the strike plate in the door frame.

It is an object of this invention to provide a tool kit by which one may quickly and easily install a strike plate in a door frame in perfect alignment with the door latch on a door such that the strike plate, when engaged by the latch bolt, will hold the door flush against a stop on the door frame to prevent rattling of the door.

The kit comprises templates for use in marking the door frame with respect to the door latch of the door and includes a jig for cutting a bolt-receiving opening in the door frame and for forming a countersink in the door frame for reception of a strike plate around the opening.

Further objects and advantages of the invention will appear during the course of the following part of this specification, wherein the details of construction and mode of operation of a preferred embodiment of the tool kit of this invention are described with reference to the accompanying drawing, in which:

FIG. 1 is a section taken on a horizontal plane through a door portion and a portion of a door frame showing the door in closed position with a latch bolt extended through a strike plate which has been installed with the use of a tool kit of this invention;

FIG. 2 is a section taken on a horizontal plane through a. door and a door frame portion and showing a template of the tool kit of this invention, the template being positioned with the door near its closed position for purposes of marking the door frame according to this invention;

FIG. 3 is a perspective view of a portion of a door frame and a marking template of the kit of this invention positioned against the door frame;

FIG. 4 is a perspective view of a portion of a door frame with a jig mechanism of the tool kit of this invention positioned against the frame for cutting a bolt-receiving hole in the frame;

FIG. 5 is another perspective view of the jig mechanlsm;

FIG. 6 is a section taken on a horizontal plane through a door frame and showing a cutting jig mechanism of this invention, partly in section, positioned against the door frame for cutting a bolt-receiving hole in the door frame;

FIG. 7 is a side elevation of the door frame taken on line 77 of FIG. 6;

FIG. 8 is a side elevation of the door frame corresponding to FIG. 7 and showing a strike plate installed in the frame;

FIG. 9 is a section taken on a horizontal plane through a door frame and showing a jig mechanism of the tool kit of this invention, partly in section, and positioned for forming a bolt-receiving opening in the door frame for a door of a different thickness than that of a door to be used in FIG. 6;

FIG. 10 is a combined top view of a door and a section through a door frame with another template of a tool kit of this invention being placed against the door frame; and

FIG. 11 is a perspective view of a portion of a door frame with the template of FIG. 10 positioned therein for marking purposes according to this invention.

Referring to the drawing in greater detail, there is shown a portion of a door frame, designated generally by reference numeral 15, and a portion of a door 16. The door has side faces 18 and 1? and a free edge surface 20, and a door latch, designated generally by reference numeral 22, installed in the door. In FIG. 1 the door is shown in its closed position, i.e., with a margin of its side face 18 abutted flush against a surface 24 of a vertically extending stop strip or molding 25 secured upon a surface 26 of the door frame.

The door latch 22 is a conventional one comprising door knobs 2S, rosettes 29, a retracting mechanism 30 disposed in a bore 31 formed in the door, and a cylindrical latch bolt assembly 32 disposed in a bore 33 which extends from the free edge surface 20 of the door to the bore 31. The latch .bolt assembly has a latch bolt 34 reciprocable axially therein and operatively connected to the retractor mechanism 30 whereby the latch bolt is actuated by turning of a door knob to pull the latch bolt within the latch bolt housing from its projected position shown in the drawing. The latch bolt has a strike surface 35 which is inclined in the direction of reciprocation. When the door is being closed, the inclined surface 35 of the latch bolt will engage a strike plate 37 on the door frame to move the bolt inwardly of the latch bolt housing until the bolt may enter an opening 38 in the strike plate to hold the door closed against the stop 25 of the door frame. In the embodiment shown, the strike plate opening has a flat or chord edge portion 39 to make the opening conform to the cross-sectional configuration of the latch bolt and against which the latch bolt becomes engaged when the door is closed.

The outside surface of the strike plate is flush with the surface 26 of the door frame, the strike plate being received in a countersink '40 formed around a hole 41 in the frame. The strike plate is a circular one of conventional design having two screws 43 by which the strike plate is secured in the countersink 40. A lip portion 44 of the strike plate extends out beyond the margin of the frame surface 26 and is bent back slightly, as shown, to provide an inclined striking surface against which the latch bolt comes in contact for moving the latch bolt inwardly of its housing as the door is being closed.

Attention is expressly directed to the relationship of the strike plate to the distance between the stop and the edge of the jamb and the thickness of the door, having particular reference to the door of lesser thickness. It is significant that the diameter of the circular portion of the strike plate be appre-cably larger than the are between the stop and the edge of the jamb so that the space therebetween is spanned by the strike plate and a substantial portion of the plate forming the lip extends over the edge. This has a further beneficial effect in providing a rather large area on the surface of the strike plate im mediately rearwardly of the lip. Good installation practice suggests that the mortise recess for the strike plate be about /32 of an inch larger than the strike plate itself for ease of installation, hence, the larger portion of the step drill will be approximately of an inch larger than 3 the diameter of the circular portion of the strike plate. This is true for both the thinner and thicker sizes of door.

It will be apparent that care must be taken in the installation of the door latch and of its associated strike plate to ensure accurate alignment of the strike plate with respect to the latch bolt so that when the door is closed the latch bolt will extend through the opening of the strike plate and into the hole 41, with the strike plate holding the door closed flush against surface 24 of the frame stop. The several parts of the tool kit of this in vention are so designed as to make it simple and easy to install the strike plate for accurate alignment with the latch bolt.

The tool kit comprises a template 54} which is designed to be positioned, as shown best in FIGS. 2 and 3, against the door frame for engagement with the door and more particularly with the horizontally extending bore 33 for the latch bolt housing, whereby a mark 51 may be made on the door frame for reference purposes in accurately positioning a jig assembly, which is designated generally by reference numeral 53 for forming the bolt receiving hole 41 and the countersink 40. The template 56 is positioned ilat against the surface 26 of the door frame with one straight edge 55 thereof abutted against the stop surface 24 of the frame, there being an upper edge 56 of the plate along which the user may draw the reference mark 51.

Template 50 has a cylindrical projection 57 integral therewith and extending out of one surface thereof and by means of which the correct vertical position for the template with respect to the bore 33 of the door may be determined. The projection is of a cross-sectional area such that it will extend into the outer end portion of the bore 33 when the edge 55 of the template is held against the frame stop and the door is slightly ajar. That position of the door provides for access to the person installing the strike plate with a marking tool for making the reference mark 51. Thus, the projection is spaced from the edge 55 of the template and is also spaced from the upper edge 56 by a predetermined distance.

After the template 50 has been employed for making the reference mark 51, the template is removed from the door frame and the drill jig is positioned against the door frame in the position shown in FIG. 4 for making the hole 41. Drill jig 53 comprises a plate 60 having front and back surfaces 61 and 62, side edge surfaces 63 and 64, and end edge surfaces 65 and 66. A block portion 68 is integral with the plate and it has an axially extending bore 69 formed therein, the axis of which is on a line perpendicular to front face 61 of the plate. A shaft 70 is extended through the opening 69, the shaft being rotatable and movable axially in the block opening. Outer end portion 71 of the shaft is adapted to be received in the chuck end of a brace or other drilling tool (not shown) for turning the shaft and exerting axially directed pressure on the shaft. A collar 73 is secured as with a set screw 74 around the shaft to serve as a stop member upon engagement with the outer end surface 75 of the block for limiting .the extent to which the shaft may be moved inwardly of the block thereby to limit the depth to which the hole 41 may be formed.

The inner end of the shaft has a slot 77 formed therein for receiving a cutting blade 78 for the jig, the blade being held in the slot as with pins 79. For the illustrated embodiment the cutting blade is of stepped construction having a pointed end portion 80, a portion 81 for cutting the hole 41, and a portion 82 for forming the countersink 40. The plate portion 60 of the jig has an opening 84 formed therein in line with a cylindrical cavity 85 formed in the block for accommodating the jig blade. As pressure is exerted on the drill stem from the outer end portion of the stem and the stem is rotated, the cutting blade will likewise be rotated and will move from within the block recess and through the opening 84 to cut the hole 41 and the countersink 40 in the door frame.

The perpendicular distance from each end edge 65 and 66 of the plate portion of the jig to the point of the cutting blade is equal to the perpendicular dimension between the upper edge 56 of the template and the center of the template projection 57. Thus, it will be apparent that when the jig is positioned as shown in 'FIG. 4 with the plane :of its end edge aligned with the reference mark 5 1, the hole 41 to be formed in the frame will be at a correct height for receiving the latch bolt of the door.

To provide for flush engagement of the door against the stop surface 24 of the door frame with the latch bolt being against the flat edge portion 39 of the strike plate opening, it is necessary that the bolt receiving hole 41 in the door frame be accurately located with respect to the stop surface. The drill jig is designed for use in installing doors of two dilferent standard thicknesses. For a thinner door the drill jig will be positioned as illustrated in FIG. 6 with its side edge 63 abutted against the stop surface. As best appears in FIG. 5, the plate opening 84 of the jig is nearer to the side edge 63 than to the side edge 64, i.e. the perpendicular distance from side edge 63 to the longitudinal axis of the drill stem is less than the perpendicular distance from the side edge 64 to the axis of the drill stem. The distance between the side edge 63 and the axis of the drill stem is equal to one-half the thickness of a standard size thinner door while the distance from side edge 64 to the axis of the drill stem is equal to one-half the thickness of a standard size thicker door. Thus, when the drill jig is positioned, as shown in FIG. 6, with its side edge 63 against the stop surface of the frame, the hole 41 and countersink 40 will be accurately spaced from the frame stop to ensure engagement of the latch bolt in the opening of the strike plate and flush engagement of the door against the frame stop. For installing a strike plate in the frame for the thicker door, the drill jig is positioned, as shown in FIG. 9, with its side edge surface 64 flush against the stop surface 24 of the door frame. In the illustrated embodiment the plate opening 84 is of such size that its circumference outs slightly through a side edge surface 63 leaving a chord opening 87 in the side edge surface 63 of the plate. Also, the jig may have a foot structure 88 projecting out from that side of the jig at which the side edge surface 63 is located, the foot 88 providing increased support surface to the jig by engagement against the stop molding 25 when the hole 41 is to be formed proximate the stop molding as in the position shown in FIG. 6.

Referring now to FlGS. l0 and 11 of the drawing, there is shown a template $6 of the tool kit of this inven tion, the template 90 being quite similar in size and shape to the template 50, but instead of having a projection for engagement with a bore in the door as in the template 50, the template 90 has an opening 91 formed therein for receiving the latch bolt of the door after the latch bolt has been installed in the door. The template 90 is employed similarly as described for the template 50, i.e. for marking reference line 51 on the door frame to indicate the proper position for the drill jig to form the bolt-receiving hole in the frame and the countersink (for the strike plate.

While I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my in ven-tion, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claim so as toembrace any and all equivalent devices.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

A drill jig for drilling a strike plate hole in a door frame at the precise elevation of a door latch, and selectively spaced from a door stop to accommodate either of two door thicknesses, which jig includes: a locating plate, said plate comprising a vertical front surface for seating against the door frame, a first vertical side wall locating surface adapted to seat against said stop when drilling for thick doors, a second vertical locating surface on the opposite side of said plate for use when drilling for :thin doors, a horizontal locating surface for elevational location of said plate, and a bore hole normal to said front surface, said bore hole having an axis between said sides, being nearer to said second than said first loeating surface and having a chordal opening insaid secend surface; a bearing block integral with the back surface of said plate, said bearing block containing bearing means for a drill shaft co-axial with the axis of said plate bore hole; a locating step on said hearing block adjacent said chordal opening in said thin door locating surface, and spaced back of said front plate surface a distance corresponding to the thickness of a door stop, and adapted to seat on the surface of a door stop when said jig is placed in position for strike hole drilling for a thin door; a drill shaft means rotatably mounted in said bearing means in said block; stop means adjustably locatable on said shaft means; and drill bit means adapted to drill a stepped hole in said door frame to a depth determined by said stop.

References Cited in the file of this patent UNITED STATES PATENTS 

